My guess is the term “Bullwheel” might come from a time when actual bulls were used to power such a wheel? At our local resort one of the on-slope restaurant/bars is called “The Bullwheel Saloon” and features an antique bullwheel outside as a yard-art decoration.
Chairlift tensioners in my experience are usually very heavy weights at the lower station, pulling back on a bullwheel assembly mounted on rails…
Chairlifts are notoriously finicky to keep running right, and ridiculously expensive to purchase and install.
The largest one at our nearest resort has not been able to be run at the design speed for several years now, with frequent stops and even reversals, chairs requiring removal during regular operation while we sit halfway up the mountain patiently waiting, and even one instance a couple years ago where everyone had to be lowered with ropes. Yes cableways of various configurations exist. Congratulations on knowing one more simple, partial fact, wannabe-AWE people.
There is a big problem with this thinking that the first to show results is on the right track.
Skysails have been going on for a long time, and have had many chances to develop their technology. They have what 100+ employees or something.
I think Skysails is doing well now because they started out building on an existent soft kite that is eas[ier] to manage than, say, the Makani kite. This is an argument that Skysails is more likely to make progress sooner. I commend Skysails for their efforts and results. But none og this proves that Skysails found some better answers than the Makani folks had. Its also a matter of execution. And how easily a goal is achieved. But, given enough hundreds of years, someone will implement something akin to the Makani machine that also excels in persormance, LCOE or whatever meteic you prefer.
I am just saying there will never be any proof that this or that is better, when there are so many unknowns. We can only make educated guesses based on what we observe and what we can deduce by logic.
And the goalposts will keep moving for all future, most probably.
You never see rigid power kites marketed, not for tank towing, not for kite-surfing, not for boat or ship towing.
The absolute failures (no generated power, crashes) of the AWE companies that have attempted to achieve significant scale with rigid kites are not due to material contingencies, some of these companies having been as well founded as SkySails.
It seems that ruthless technological Darwinism is at work: just as the power kite market has retained only the soft kites, it seems that the same is true for AWES at least in their current phase of evolution. I don’t see what could reverse the trend.
Well what you say makes little sense. If you think about kitesurfing markets you have single foil, foil kites and LEI kites all serving their purposes. Why would any traction sport go for a rigid kite? It would be dangerous and probably quite expensive, and require electric stabilization. So again, the power kite market going «soft» proves nothing.
I would also say, no need to hedge your bets saying «in this phase of the AWE evolution». It seems in this phase we are all dabbling with ideas trying to find something that will stick to the wall.
Saying this or that proves anything at this point is nonsensical.
I am only stating what is verifiable. I don’t write nonsense like that:
Please tell me why you consider that to be nonsense?
Funny you should mention that. I just had another hour-long phone call with a hang-gliding friend who is also an aero-inventor. He was musing about using a propeller as a drogue 'chute that could charge up a capacitor and give you a quick boost for say, clearing a powerline (big problem for hang-gliders). I told him propellers usually only work well for either propulsion or as a wind turbine, hard to get both in one package, mentioning Makani, but suddenly I thought of what may be a new way, that I do not think anyone has tried. If so, I haven’t heard about it. This could be yet another “great invention”! (Hope it works better than my snowboard idea…)
Hope its not the same as my invention along the same lines solving the same issue…
Don’t worry about it. I already patented the concept back In the 80ties
Sounds interesting - how can we see it? 
Perhaps individual AWES (Kiwee like, but more powerful, 2-10 kW range, to partially feed a house or an electric car or van) would be a possibility.
This topic is now over 4 years old. From a marketing point of view, there are no new elements to my knowledge. Which in itself can lead to clarification. The market has given its point of view.
My take is that traditional HAWT wind turbines work well and should not be challenged with AWES for comparable altitudes and winds: their efficiency is higher, which is normal since all the wind energy captured is devolved to electricity production.
Things may be different for truly high altitude winds, say above 2000 m but below the altitude of airliners. A now old publication details the reasons.
3.1. Global Vertical Profiles
First, we analyze the profile of global average wind power density by level (Figure 2a), obtained by averaging, for each percentile, the wind power density over all latitudes and longitudes. The highest wind power densities are found at altitudes between 8,000 and 10,000 m above ground, corresponding roughly to the height of the tropopause. The 10,000 m altitude appears to be the maximum height that is worth exploring for high-altitude wind power technologies.
Whereas above 2,000 m wind power density increases monotonically with height, the altitude range between 500 and 2,000 m has relatively constant wind power densities, with actually a slight decline between 500 and 1,500 m for median and slower winds (i.e., winds available ≥ 50% of the time). This finding, consistent with [5, 6] for several sites in Europe, suggests that, on average, there may not be much benefit in going higher than 500 m, unless reaching above 2,000 m.
Although the most rapid increase in wind power density with altitude occurs between 6,000 and 7,000 m (for median winds, +0.37 W/m² for each m increase in altitude), going from 80 to 500 m also gives a significant increase in wind power density (+0.25 W/m²/m for median winds).
Now the new giant HAWT reach easily 200 m and more. It would now be necessary to analyze whether AWES flying at 500 m altitude could be more productive thanks to the wind surplus and despite the relative weakness of their efficiency. We could then design crosswind systems like MAWES, including several SkySails kites.
As between 500 m and 2000 m not much happens, let’s move on to the level above, from 2000 m, and let say up to 6-7 km. With such energy densities, and also such tether lengths, more static AWES may be preferred, as was the case in its time for Sky WindPower.
But all this must be sufficiently light, and with simple, non-conductive tethers, in pumping mode, and “sweep” a large area. For that I would see a Parasail-based Airborne Wind Energy System, as an improvement of Zhonglu HAWP Technology, by using special shapes for high drag and lift coefficients.
Of course parasail-based AWES would be tested in first at lower altitudes, but without being able to hope for any market, this type of device can only be effective with strong high altitude winds.
So because in four years nothing happened we can conclude that AWE is dead? I think this is not a good argument, just more «im tired of waiting for results lets conclude its not possible».
I find it odd that you make this statement shortly after Skysails released their power curve that is verified and also it seems with the best power to mass ratio for wind power so far. Seems to me you just decided AWE was not possible long ago. Now just keep arguing why you were right.
In my opinion, the jury is still out on AWE. And the next 30 years may not give us a definitive answer even…
I no longer have too many illusions about the future of e-AWE in large-scale power generation, but I’m at least looking for ideas, such as a high drag coefficient to increase power while keeping things relatively simple.
And 15 years of attempts is more than enough time to separate the wheat (if there is any) from the chaff. The chaff will not become wheat, even after another 30 years.
Things are simple, for AWE concepts as elsewhere: it’s either good or bad.
The problem with all groundgen systems is that if we try to operate at higher altitudes, the cosine cubed losses are more than the increase in power due to higher wind velocity. This is because in order to gain altitude we must increase the tether angle. Alternately we can try to operate with long tethers at a low tether angle but this increases the weight of the tether and the sag in the tether increases the cosine cubed losses. The only alternative is to use the Kiwi style system where the turbines are oriented to face the wind and there are no cosine cubed losses.
Highest Altitude - Single Kite Box Kites 12,471 feet, more than 2 miles!!
Highest Altitude - Kite Train 8 Box Kites 31,955 feet, more than 6 miles!!
Groudgen systems using kite trains like Parasail-based Airborne Wind Energy System could reach higher altitudes because the tether is carried by kites over a good part of its length. This system would work at a low angle of elevation of 30 degrees, leading to 2 times tether length for 1 time height. This angle is comparable to that of crosswind kites.
This is the price to pay for more power with equal equipment, knowing that for any AWES, any capture of wind energy results in a horizontal force component which is that of the wind.
For the Kiwee, it is necessary to add a turbine to the lifting kite, and this turbine will quickly be subject to scale limitations by increasing weight by square-cube law, leading to the requirement of a bigger and bigger lifting kite, in addition to said turbine. If you want to decrease the lifting area of the kite relative to the area swept by the turbine, the elevation angle will decrease, leading to possible complications due to the weight of the turbine while the lift force becomes lesser compared to other forces, leading to a higher cut-in wind speed by a far higher wing loading, increasing crash risk when the wind speed weakens.
The problem is the same for any kind of AWE system.
The Kiwi design would require a large lifter for high elevation angles. That would be similar to cosine losses, except now maybe call it lifter losses?
The turbine blades could be optimized for less downwind drag. This means less power per swept area though. Same could apply to AWE I guess.
The only escape for this would be some AWE design that produces power mostly straight up, maybe accessing jet streams. But that kind of turbine would face a lot of problems, my first concern would be controlling power (the minmax problem, named so by Peter Lynn Sr)